chromium中增加默认主题的一个方法

首先，chromium除了默认主题外，其它都是以chrome拓展的方式安装的，所以对于一个新的主题，需要定一个主题id，这个主题id可以先自己定一个，只要长度一致就可以了，但是主题id会有字母范围的限制，所以可以找一个现成的id，然后直接交换几个字母的位置就可以，后继这个id并不会真正用到。

src\chrome\browser\themes\theme_service.cc
const char* ThemeService::kDefaultThemeID = "";
const char* ThemeService::kNewDefaultThemeID = "ndoippcjlipfddffdcimakhebaemnmgn";

src\chrome\browser\themes\theme_service_factory.cc
  registry->RegisterStringPref(
      prefs::kCurrentThemeID,
	  ThemeService::kNewDefaultThemeID,
      user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);

void ThemeService::MigrateTheme() {
  // TODO(erg): We need to pop up a dialog informing the user that their
  // theme is being migrated.
  ExtensionService* service =
      extensions::ExtensionSystem::Get(profile_)->extension_service();
  const Extension* extension = service ?
      service->GetExtensionById(GetThemeID(), false) : NULL;
  if (extension) {
    DLOG(ERROR) << "Migrating theme";
    BuildFromExtension(extension);
    content::RecordAction(UserMetricsAction("Themes.Migrated"));
  } else {
	if (GetThemeID() == kNewDefaultThemeID) {
		base::FilePath dir_exe;
		PathService::Get(base::DIR_EXE, &dir_exe);
		base::FilePath new_theme_dir(dir_exe.value() + FILE_PATH_LITERAL("/new_theme"));
		extensions::UnpackedInstaller::Create(service)->Load(new_theme_dir);
	} else {
		  DLOG(ERROR) << "Theme is mysteriously gone.";
		  ClearAllThemeData();
		  content::RecordAction(UserMetricsAction("Themes.Gone"));
    }
  }
}

void ThemeService::ClearAllThemeData() {
  if (!ready_)
    return;
  SwapThemeSupplier(NULL);
  FreePlatformCaches();
  profile_->GetPrefs()->ClearPref(prefs::kCurrentThemePackFilename);
  SaveThemeID(kNewDefaultThemeID);
  base::MessageLoop::current()->PostTask(FROM_HERE,
	  base::Bind(&ThemeService::RemoveUnusedThemes,
	  weak_ptr_factory_.GetWeakPtr(),
	  true));
  MigrateTheme();
}

chromium中增加默认主题的一个方法

原文：http://blog.csdn.net/ljm198745/article/details/44410757